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401: Excess Graywater (Larger Properties)

“Instead of dumping excess graywater into the septic system during winter, excess graywater can be sub surface irrigated to disposal zones.”

“Reducing the amount of graywater entering the septic year run can significantly reduce septic maintenance requirements, savings thousands in maintenance costs.”

“Some Commercial Applications, e.g. Hotels, are charged for graywater disposal, and onsite disposal of excess graywater via sub surface zones can reduce costs significantly.”

While we want every drop of graywater in summer, winter can present a challenge.

If you have a cold winter location, where very little irrigation is required, excess graywater can automatically be diverted to waste. However if the property has a septic waste system, this excess graywater adds load to the septic. Keeping the graywater away from the septic throughout the year can significantly reduce septic maintenance costs.

Instead of having excess graywater being pumped directly to waste, IrriGRAY allows additional irrigation zones to be used just for excess graywater disposal. These zones typically have 500' to 1,000' of Netafim Bioline 0.6 gph dripperline installed between 5" and 24" below ground level. In all cases the depth must exceed the hard freeze depth.

IrriGRAY then diverts this excess graywater (or all graywater if the temperature has dropped below freezing conditions, and no other 'freeze capable' zones are present) to excess graywater zones.

IrriGRAY University

For each month of the year, excess graywater can added to standard graywater zones automatically, or sent to waste. 

If the property is experiencing freezing conditions, all graywater can be sent to waste (standard - as displayed here with the freeze to waste check-box ticked), or instead be sent to freeze capable zones first - if available - or to additional waste zones established.

Please note: for graywater to be processed via dripperlines in freezing conditions, the filter assembly but in a warm location to prevent freezing of the filter body.

By default - freeze to waste is turned on - and the filter is automatically placed into freeze protect mode, emptying itself so expanding water / ice will not cause a problem.

Zones are defined as being of type graywater dripperline, graywater disposal, potable sprinkler and potable dripperline (mainly for vegetable gardens).

The zone type is selected from Graywater Dripperline, Graywater Disposal, Potable Water Sprinkler and Potable Water Dripperline.

In this example, this zone has not been set as freeze capable, and therefore will not receive any graywater during freezing conditions.

This image shows how a zone can be setup as a graywater disposal zone - keeping graywater away from a septic all year.

Note this zone can be set as being freeze capable - or not. This means a near surface irrigation zone, such as landscape bed installed on the dirt surface but covered by 2" of mulch or similar covering, can be used to dispose of excess graywater. In this case, if freezing conditions develop, excess graywater will not be sent to this zone. If no other zones are freeze capable, excess graywater will automatically be pumped to waste.

Some commercial graywater facilities, such as hotel laundries & laundromats experience significant waste water disposal fees. Check with local authorities to see if they allow reduced disposal fees when all graywater is used on site instead of disposal via the sewer system.

Note: Graywater which is pumped directly to waste (sewer or septic) does not pass through the filter and water meter assembly, and is therefore not measured. Excess graywater that is used for irrigation or onsite disposal using graywater disposal zones is metered and shown on IrriGRAY charts / graphs.

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